20 online services for color selection

Material Palette
Generator and export color palette in material design style.
http://www.materialpalette.com/

New Flat UI Color Picker
The best colors for flat style interfaces.
http://www.flatuicolorpicker.com/

Flat UI Colors
Beautiful colors in flat style.
http://flatuicolors.com/

Coolors:
Super fast color scheme generator for cool designers.
https://coolors.co/

Color scale
Unusual selection of colors.
https://bjango.com/mac/skalacolor/

Colors
Simple applications to determine the colors you see on the screen.
http://couleursapp.com/

Material UI Colors
Color palette for Android, web and iOS in the style of material design
https://www.materialui.co/colors

Colorful Gradients
Automatic gradient creation.
http://colorfulgradients.tumblr.com/

Brand Colors
Colors used by famous brands.
http://brandcolors.net/

Paletton
Creating a color scheme.
http://paletton.com/#uid=1000u0kllllaFw0g0qFqFg0w0aF

0 to 255
A simple tool for finding color shades.
http://www.0to255.com/

Color Lovers
Create and share colors, palettes, and patterns.
http://www.colourlovers.com/

Adobe Color CC
Color combinations from the Kuler community.
https://color.adobe.com/ru/create/color-wheel/

Boat flat
Perfect colors in flat style.
http://bootflat.github.io/color-picker.html

Hex Colorrrs
Converter from Hex to RGB.
http://hex.colorrrs.com/

Get UI Colors
Find matching colors for interfaces.
http://getuicolors.com/

Colors
Clever selection of colors.
https://www.coleure.com/

Colllor
Color palette generator.
http://colllor.com/